容器编排系统之Kubernetes基础入门
一、kubernetes简介
1、什么是kubernetes？它是干什么用的？
kubernetes是google公司用go语言开发的一套容器编排系统，简称k8s；它主要用于容器编排；所谓容器编排简单的我们可以理解为管理容器；这个有点类似openstack，不同的是openstack是用来管理虚拟机，而k8s中是管理的pod（所谓pod就是容器的一个外壳，里面可以跑一个或多个容器，可以理解为pod就是将一个或多个容器逻辑的组织在一起）；k8s除了可以全生命周期的管理pod，它还可以实现pod的自动化部署，自动修复以及动态的扩缩容等功能；
2、k8s架构
提示：k8s是master/node模型，master是整个k8s的管理端，其上主要运行etcd，api server ，scheduler，controllermanager以及网络相关插件；其中etcd是一个kv键值存储数据库，主要存放k8s中所有配置信息以及pod状态信息，一旦etcd宕机，k8s整个系统将不可用；apiserver主要用来接收客户端请求，也是k8s中唯一的入口；用户的所有管理操作都是将请求发送给apiserver；scheduler主要用来调度用户请求，比如用户要在k8s系统上运行一个pod，至于这个pod该运行在那个node节点，这个就需要scheduler的调度；controllermanager主要用来管理以及监控pod状态；对于scheduler调度的结果，controlmanager就负责让对应节点上的对应pod精准处于调度的状态；node的节点是k8s的工作节点，主要用于运行pod；node节点主要运行的应用有docker，kubelet,kube-proxy；其中docker是用来运行容器的，kubelet主要负责执行master端controllermanager下发的任务；kube-proxy主要用来生成pod网络相关iptables或ipvs规则的；
3、k8s工作过程
提示：k8s工作过程如上图所示，首先用户将请求通过https发送给apiserver，apiserver收到请求后，首先要验证客户端证书，如果通过验证，然后再检查用户请求的资源是否满足对应api请求的语法，满足则就把对应的请求资源以及资源状态信息存放在etcd中；scheduler和controllermanager以及kubelet这三个组件会一直监视着apiserver上的资源变动，一旦发现有合法的请求进来，首先scheduler会根据用户请求的资源，来评判该资源该在那个节点上创建，然后scheduler把对应的调度信息发送给apiserver，然后controllermanager结合scheduler的调度信息，把对应创建资源的方法也发送给apiserver；最后是各节点上的kubelet通过scheduler的调度信息来判断对应资源是否在本地执行，如果是，它就把controllermanager发送给apiserver的创建资源的方法在本地执行，把对应的资源在本地跑起来；后续controllermanager会一直监视着对应的资源是否健康，如果对应资源不健康，它会尝试重启资源，或者重建资源，让对应资源处于我们定义的状态；
二、k8s集群搭建
1、部署说明
部署k8s集群的方式有两种，一种是在各节点上把对应的组件运行为容器的形式；第二种是将各组件运行为守护进程的方式；对于不同的环境我们部署的方式也有不同，对于测试环境，我们可以使用单master节点，单etcd实例，node节点按需而定；生产环境首先是etcd要高可用，我们要创建etcd高可用集群，一般创建3个或5个或7个节点；其次master也要高可用，高可用master我们需要注意apiserver是无状态的可多实例，前端使用nginx或haproxy做调度即可；对于scheduler和controller这两个组件各自只能有一个活动实例，如果是多个实例，其余的只能是备用；
测试环境部署k8s，将各组件运行为容器
环境说明
| 主机名 | IP地址 | 角色 |
| master01.k8s.org | 192.168.0.41 | master |
| node01.k8s.org | 192.168.0.44 | node01 |
| node02.k8s.org | 192.168.0.45 | node02 |
| node03.k8s.org | 192.168.0.46 | node03 |
各节点主机名解析
[root@master01 ~]# cat /etc/hosts
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
192.168.0.99 time.test.org time-node
192.168.0.41 master01 master01.k8s.org
192.168.0.42 master02 master02.k8s.org
192.168.0.43 master03 master03.k8s.org
192.168.0.44 node01 node01.k8s.org
192.168.0.45 node02 node02.k8s.org
192.168.0.46 node03 node03.k8s.org
[root@master01 ~]#
各节点时间同步
[root@master01 ~]# grep server /etc/chrony.conf
# Use public servers from the pool.ntp.org project.
server time.test.org iburst
# Serve time even if not synchronized to any NTP server.
[root@master01 ~]# chronyc sources
210 Number of sources = 1
MS Name/IP address Stratum Poll Reach LastRx Last sample
===============================================================================
^~ time.test.org 3 6 377 56 -6275m[ -6275m] +/- 20ms
[root@master01 ~]# ssh node01 'chronyc sources'
210 Number of sources = 1
MS Name/IP address Stratum Poll Reach LastRx Last sample
===============================================================================
^~ time.test.org 3 6 377 6 -6275m[ -6275m] +/- 20ms
[root@master01 ~]# ssh node02 'chronyc sources'
210 Number of sources = 1
MS Name/IP address Stratum Poll Reach LastRx Last sample
===============================================================================
^~ time.test.org 3 6 377 41 -6275m[ -6275m] +/- 20ms
[root@master01 ~]# ssh node03 'chronyc sources'
210 Number of sources = 1
MS Name/IP address Stratum Poll Reach LastRx Last sample
===============================================================================
^~ time.test.org 3 6 377 35 -6275m[ -6275m] +/- 20ms
[root@master01 ~]#
提示：有关时间同步服务器的搭建请参考https://www.cnblogs.com/qiuhom-1874/p/12079927.html；ssh互信请参考https://www.cnblogs.com/qiuhom-1874/p/11783371.html；
各节点关闭selinux
[root@master01 ~]# cat /etc/selinux/config # This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
# enforcing - SELinux security policy is enforced.
# permissive - SELinux prints warnings instead of enforcing.
# disabled - No SELinux policy is loaded.
SELINUX=disabled
# SELINUXTYPE= can take one of three two values:
# targeted - Targeted processes are protected,
# minimum - Modification of targeted policy. Only selected processes are protected.
# mls - Multi Level Security protection.
SELINUXTYPE=targeted [root@master01 ~]# getenforce
Disabled
[root@master01 ~]#
提示：将/etc/selinux/config中的SELINUX=enforcing修改成SELINUX=disabled，然后重启主机或者执行setenforce 0；
关闭iptabels服务或firewalld服务
[root@master01 ~]# systemctl status firewalld
● firewalld.service - firewalld - dynamic firewall daemon
Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor preset: enabled)
Active: inactive (dead)
Docs: man:firewalld(1)
[root@master01 ~]# iptables -nvL
Chain INPUT (policy ACCEPT 650 packets, 59783 bytes)
pkts bytes target prot opt in out source destination Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination Chain OUTPUT (policy ACCEPT 503 packets, 65293 bytes)
pkts bytes target prot opt in out source destination
[root@master01 ~]# ssh node01 'systemctl status firewalld'
● firewalld.service - firewalld - dynamic firewall daemon
Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor preset: enabled)
Active: inactive (dead)
Docs: man:firewalld(1)
[root@master01 ~]# ssh node02 'systemctl status firewalld'
● firewalld.service - firewalld - dynamic firewall daemon
Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor preset: enabled)
Active: inactive (dead)
Docs: man:firewalld(1)
[root@master01 ~]# ssh node03 'systemctl status firewalld'
● firewalld.service - firewalld - dynamic firewall daemon
Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor preset: enabled)
Active: inactive (dead)
Docs: man:firewalld(1)
[root@master01 ~]#
提示：将firewalld服务停掉并设置为开机禁用；并确保iptables规则表中没有任何规则；
各节点下载docker仓库配置文件
[root@master01 ~]# wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo
--2020-12-08 14:04:29-- https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
Resolving mirrors.aliyun.com (mirrors.aliyun.com)... 182.140.140.242, 110.188.26.241, 125.64.1.228, ...
Connecting to mirrors.aliyun.com (mirrors.aliyun.com)|182.140.140.242|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 2640 (2.6K) [application/octet-stream]
Saving to: ‘/etc/yum.repos.d/docker-ce.repo’ 100%[======================================================================>] 2,640 --.-K/s in 0s 2020-12-08 14:04:30 (265 MB/s) - ‘/etc/yum.repos.d/docker-ce.repo’ saved [2640/2640] [root@master01 ~]# ssh node01 'wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo'
--2020-12-08 14:04:42-- https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
Resolving mirrors.aliyun.com (mirrors.aliyun.com)... 182.140.139.60, 125.64.1.228, 118.123.2.185, ...
Connecting to mirrors.aliyun.com (mirrors.aliyun.com)|182.140.139.60|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 2640 (2.6K) [application/octet-stream]
Saving to: ‘/etc/yum.repos.d/docker-ce.repo’ 0K .. 100% 297M=0s 2020-12-08 14:04:42 (297 MB/s) - ‘/etc/yum.repos.d/docker-ce.repo’ saved [2640/2640] [root@master01 ~]# ssh node02 'wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo'
--2020-12-08 14:04:38-- https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
Resolving mirrors.aliyun.com (mirrors.aliyun.com)... 182.140.139.59, 118.123.2.183, 182.140.140.238, ...
Connecting to mirrors.aliyun.com (mirrors.aliyun.com)|182.140.139.59|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 2640 (2.6K) [application/octet-stream]
Saving to: ‘/etc/yum.repos.d/docker-ce.repo’ 0K .. 100% 363M=0s 2020-12-08 14:04:38 (363 MB/s) - ‘/etc/yum.repos.d/docker-ce.repo’ saved [2640/2640] [root@master01 ~]# ssh node03 'wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo'
--2020-12-08 14:04:43-- https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
Resolving mirrors.aliyun.com (mirrors.aliyun.com)... 118.123.2.184, 182.140.140.240, 182.140.139.63, ...
Connecting to mirrors.aliyun.com (mirrors.aliyun.com)|118.123.2.184|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 2640 (2.6K) [application/octet-stream]
Saving to: ‘/etc/yum.repos.d/docker-ce.repo’ 0K .. 100% 218M=0s 2020-12-08 14:04:43 (218 MB/s) - ‘/etc/yum.repos.d/docker-ce.repo’ saved [2640/2640] [root@master01 ~]#
创建kubernetes仓库配置文件
[root@master01 yum.repos.d]# cat kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
[root@master01 yum.repos.d]#
复制kubernetes仓库配置文件到各node节点
[root@master01 yum.repos.d]# scp kubernetes.repo node01:/etc/yum.repos.d/
kubernetes.repo 100% 276 87.7KB/s 00:00
[root@master01 yum.repos.d]# scp kubernetes.repo node02:/etc/yum.repos.d/
kubernetes.repo 100% 276 13.6KB/s 00:00
[root@master01 yum.repos.d]# scp kubernetes.repo node03:/etc/yum.repos.d/
kubernetes.repo 100% 276 104.6KB/s 00:00
[root@master01 yum.repos.d]#
在各节点安装docker-ce，kubectl，kubelet，kubeadm
yum install -y docker-ce kubectl kubeadm kubelet
编辑docker unitfile文件，加上启动docker后执行iptables -P FORWARD ACCEPT
复制docker.service到各节点
[root@master01 ~]# scp /usr/lib/systemd/system/docker.service node01:/usr/lib/systemd/system/docker.service
docker.service 100% 1764 220.0KB/s 00:00
[root@master01 ~]# scp /usr/lib/systemd/system/docker.service node02:/usr/lib/systemd/system/docker.service
docker.service 100% 1764 359.1KB/s 00:00
[root@master01 ~]# scp /usr/lib/systemd/system/docker.service node03:/usr/lib/systemd/system/docker.service
docker.service 100% 1764 792.3KB/s 00:00
[root@master01 ~]#
配置docker加速器
[root@master01 ~]# mkdir /etc/docker
[root@master01 ~]# cd /etc/docker
[root@master01 docker]# cat >> daemon.json << EOF
> {
> "registry-mirrors": ["https://cyr1uljt.mirror.aliyuncs.com"]
> }
> EOF
[root@master01 docker]# cat daemon.json
{
"registry-mirrors": ["https://cyr1uljt.mirror.aliyuncs.com"]
}
[root@master01 docker]#
在各节点上创建/etc/docker目录，并复制master端上daemon.json文件到各节点
[root@master01 docker]# ssh node01 'mkdir /etc/docker'
[root@master01 docker]# ssh node02 'mkdir /etc/docker'
[root@master01 docker]# ssh node03 'mkdir /etc/docker'
[root@master01 docker]# scp daemon.json node01:/etc/docker/
daemon.json 100% 65 30.6KB/s 00:00
[root@master01 docker]# scp daemon.json node02:/etc/docker/
daemon.json 100% 65 52.2KB/s 00:00
[root@master01 docker]# scp daemon.json node03:/etc/docker/
daemon.json 100% 65 17.8KB/s 00:00
[root@master01 docker]#
各节点启动docker，并设置为开机启动
[root@master01 docker]# systemctl enable docker --now
Created symlink from /etc/systemd/system/multi-user.target.wants/docker.service to /usr/lib/systemd/system/docker.service.
[root@master01 docker]# ssh node01 'systemctl enable docker --now'
Created symlink from /etc/systemd/system/multi-user.target.wants/docker.service to /usr/lib/systemd/system/docker.service.
[root@master01 docker]# ssh node02 'systemctl enable docker --now'
Created symlink from /etc/systemd/system/multi-user.target.wants/docker.service to /usr/lib/systemd/system/docker.service.
[root@master01 docker]# ssh node03 'systemctl enable docker --now'
Created symlink from /etc/systemd/system/multi-user.target.wants/docker.service to /usr/lib/systemd/system/docker.service.
[root@master01 docker]#
验证各节点docker是加速器是否应用？
[root@master01 docker]# docker info |grep aliyun
https://cyr1uljt.mirror.aliyuncs.com/
[root@master01 docker]# ssh node01 'docker info |grep aliyun'
https://cyr1uljt.mirror.aliyuncs.com/
[root@master01 docker]# ssh node02 'docker info |grep aliyun'
https://cyr1uljt.mirror.aliyuncs.com/
[root@master01 docker]# ssh node03 'docker info |grep aliyun'
https://cyr1uljt.mirror.aliyuncs.com/
[root@master01 docker]#
提示：在对应节点执行docker info命令能够看到对应的加速器地址，说明加速器应用成功；
验证所有节点iptables FORWARD链默认规则是否是ACCEPT
[root@master01 docker]# iptables -nvL|grep FORWARD
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
[root@master01 docker]# ssh node01 'iptables -nvL|grep FORWARD'
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
[root@master01 docker]# ssh node02 'iptables -nvL|grep FORWARD'
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
[root@master01 docker]# ssh node03 'iptables -nvL|grep FORWARD'
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
[root@master01 docker]#
添加内核参数配置文件，并复制配置文件到其他节点
[root@master01 ~]# cat /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
[root@master01 ~]# scp /etc/sysctl.d/k8s.conf node01:/etc/sysctl.d/k8s.conf
k8s.conf 100% 79 25.5KB/s 00:00
[root@master01 ~]# scp /etc/sysctl.d/k8s.conf node02:/etc/sysctl.d/k8s.conf
k8s.conf 100% 79 24.8KB/s 00:00
[root@master01 ~]# scp /etc/sysctl.d/k8s.conf node03:/etc/sysctl.d/k8s.conf
k8s.conf 100% 79 20.9KB/s 00:00
[root@master01 ~]#
应用内核参数使其生效
[root@master01 ~]# sysctl -p /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
[root@master01 ~]# ssh node01 'sysctl -p /etc/sysctl.d/k8s.conf'
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
[root@master01 ~]# ssh node02 'sysctl -p /etc/sysctl.d/k8s.conf'
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
[root@master01 ~]# ssh node03 'sysctl -p /etc/sysctl.d/k8s.conf'
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
[root@master01 ~]#
配置kubelet，让其忽略swap开启报错
[root@master01 ~]# cat /etc/sysconfig/kubelet
KUBELET_EXTRA_ARGS="--fail-swap-on=false"
[root@master01 ~]# scp /etc/sysconfig/kubelet node01:/etc/sysconfig/kubelet
kubelet 100% 42 12.2KB/s 00:00
[root@master01 ~]# scp /etc/sysconfig/kubelet node02:/etc/sysconfig/kubelet
kubelet 100% 42 16.2KB/s 00:00
[root@master01 ~]# scp /etc/sysconfig/kubelet node03:/etc/sysconfig/kubelet
kubelet 100% 42 11.2KB/s 00:00
[root@master01 ~]#
查看kubelet版本
[root@master01 ~]# rpm -q kubelet
kubelet-1.20.0-0.x86_64
[root@master01 ~]#
初始化master节点
[root@master01 ~]# kubeadm init --pod-network-cidr="10.244.0.0/16" \
> --kubernetes-version="v1.20.0" \
> --image-repository="registry.aliyuncs.com/google_containers" \
> --ignore-preflight-errors=Swap
提示：初始化master需要注意，默认不指定镜像仓库地址它会到k8s.gcr.io这个仓库中下载对应组件的镜像；gcr.io这个地址是google的仓库，在国内一般是无法正常连接；
提示：一定要看到初始化成功的提示才表示master初始化没有问题；这里还需要将最后的kubeadm join 这条命令记录下来，后续加node节点需要用到这个命令；
在当前用户家目录下创建.kube目录，并复制kubectl配置文件到.kube目录下命名为config
[root@master01 ~]# mkdir -p $HOME/.kube
[root@master01 ~]# cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
提示：复制配置文件的主要原因是我们要在master端用kubectl命令来管理集群，配置文件中包含证书信息以及对应master的地址，默认执行kubctl命令会在当前用户的家目录查找config配置文件，只有当kubectl验证成功后才可以正常管理集群；如果不是root用户，是其他普通用户，还需要将config文件的属主和属组修改成对应的用户；
安装flannel插件
[root@master01 ~]# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
The connection to the server raw.githubusercontent.com was refused - did you specify the right host or port?
[root@master01 ~]#
提示：这里提示raw.githubusercontent.com不能访问，解决办法在/etc/hosts文件中加入对应的解析记录
添加raw.githubusercontent.com的解析
[root@master01 ~]# cat /etc/hosts
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
192.168.0.99 time.test.org time-node
192.168.0.41 master01 master01.k8s.org
192.168.0.42 master02 master02.k8s.org
192.168.0.43 master03 master03.k8s.org
192.168.0.44 node01 node01.k8s.org
192.168.0.45 node02 node02.k8s.org
192.168.0.46 node03 node03.k8s.org
151.101.76.133 raw.githubusercontent.com
[root@master01 ~]#
再次执行kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml命令
[root@master01 ~]# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
Unable to connect to the server: read tcp 192.168.0.41:46838->151.101.76.133:443: read: connection reset by peer
[root@master01 ~]#
提示：这里还是提示我们不能连接；解决办法，用浏览器打开 https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml，将其内容复制出来，然后在当前目录下创建flannel.yml文件
flannel.yml文件内容
[root@master01 ~]# cat flannel.yml
---
apiVersion: policy/v1beta1
kind: PodSecurityPolicy
metadata:
name: psp.flannel.unprivileged
annotations:
seccomp.security.alpha.kubernetes.io/allowedProfileNames: docker/default
seccomp.security.alpha.kubernetes.io/defaultProfileName: docker/default
apparmor.security.beta.kubernetes.io/allowedProfileNames: runtime/default
apparmor.security.beta.kubernetes.io/defaultProfileName: runtime/default
spec:
privileged: false
volumes:
- configMap
- secret
- emptyDir
- hostPath
allowedHostPaths:
- pathPrefix: "/etc/cni/net.d"
- pathPrefix: "/etc/kube-flannel"
- pathPrefix: "/run/flannel"
readOnlyRootFilesystem: false
# Users and groups
runAsUser:
rule: RunAsAny
supplementalGroups:
rule: RunAsAny
fsGroup:
rule: RunAsAny
# Privilege Escalation
allowPrivilegeEscalation: false
defaultAllowPrivilegeEscalation: false
# Capabilities
allowedCapabilities: ['NET_ADMIN', 'NET_RAW']
defaultAddCapabilities: []
requiredDropCapabilities: []
# Host namespaces
hostPID: false
hostIPC: false
hostNetwork: true
hostPorts:
- min: 0
max: 65535
# SELinux
seLinux:
# SELinux is unused in CaaSP
rule: 'RunAsAny'
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: flannel
rules:
- apiGroups: ['extensions']
resources: ['podsecuritypolicies']
verbs: ['use']
resourceNames: ['psp.flannel.unprivileged']
- apiGroups:
- ""
resources:
- pods
verbs:
- get
- apiGroups:
- ""
resources:
- nodes
verbs:
- list
- watch
- apiGroups:
- ""
resources:
- nodes/status
verbs:
- patch
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: flannel
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: flannel
subjects:
- kind: ServiceAccount
name: flannel
namespace: kube-system
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: flannel
namespace: kube-system
---
kind: ConfigMap
apiVersion: v1
metadata:
name: kube-flannel-cfg
namespace: kube-system
labels:
tier: node
app: flannel
data:
cni-conf.json: |
{
"name": "cbr0",
"cniVersion": "0.3.1",
"plugins": [
{
"type": "flannel",
"delegate": {
"hairpinMode": true,
"isDefaultGateway": true
}
},
{
"type": "portmap",
"capabilities": {
"portMappings": true
}
}
]
}
net-conf.json: |
{
"Network": "10.244.0.0/16",
"Backend": {
"Type": "vxlan"
}
}
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: kube-flannel-ds
namespace: kube-system
labels:
tier: node
app: flannel
spec:
selector:
matchLabels:
app: flannel
template:
metadata:
labels:
tier: node
app: flannel
spec:
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: kubernetes.io/os
operator: In
values:
- linux
hostNetwork: true
priorityClassName: system-node-critical
tolerations:
- operator: Exists
effect: NoSchedule
serviceAccountName: flannel
initContainers:
- name: install-cni
image: quay.io/coreos/flannel:v0.13.1-rc1
command:
- cp
args:
- -f
- /etc/kube-flannel/cni-conf.json
- /etc/cni/net.d/10-flannel.conflist
volumeMounts:
- name: cni
mountPath: /etc/cni/net.d
- name: flannel-cfg
mountPath: /etc/kube-flannel/
containers:
- name: kube-flannel
image: quay.io/coreos/flannel:v0.13.1-rc1
command:
- /opt/bin/flanneld
args:
- --ip-masq
- --kube-subnet-mgr
resources:
requests:
cpu: "100m"
memory: "50Mi"
limits:
cpu: "100m"
memory: "50Mi"
securityContext:
privileged: false
capabilities:
add: ["NET_ADMIN", "NET_RAW"]
env:
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
volumeMounts:
- name: run
mountPath: /run/flannel
- name: flannel-cfg
mountPath: /etc/kube-flannel/
volumes:
- name: run
hostPath:
path: /run/flannel
- name: cni
hostPath:
path: /etc/cni/net.d
- name: flannel-cfg
configMap:
name: kube-flannel-cfg [root@master01 ~]#
使用 flannel.yml文件来安装flannel插件
[root@master01 ~]# kubectl apply -f flannel.yml
podsecuritypolicy.policy/psp.flannel.unprivileged created
clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/flannel created
serviceaccount/flannel created
configmap/kube-flannel-cfg created
daemonset.apps/kube-flannel-ds created
[root@master01 ~]#
查看master端运行的pod情况
[root@master01 ~]# kubectl get pods -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-7f89b7bc75-k9gdt 0/1 Pending 0 30m
coredns-7f89b7bc75-kp855 0/1 Pending 0 30m
etcd-master01.k8s.org 1/1 Running 0 30m
kube-apiserver-master01.k8s.org 1/1 Running 0 30m
kube-controller-manager-master01.k8s.org 1/1 Running 0 30m
kube-flannel-ds-zgq92 0/1 Init:0/1 0 9m45s
kube-proxy-pjv9s 1/1 Running 0 30m
kube-scheduler-master01.k8s.org 1/1 Running 0 30m
[root@master01 ~]#
提示：这里可以看到kube-flannel一直在初始化，原因是在flannel.yml资源清单中使用的是quay.io/coreos/flannel:v0.13.1-rc1这个镜像，这个镜像仓库在国内访问速度非常慢，有时候几乎就下载不到对应的镜像；解决办法，翻墙出去把对应镜像打包，然后再导入镜像；
导入 quay.io/coreos/flannel:v0.13.1-rc镜像
[root@master01 ~]# ll
total 64060
-rw------- 1 root root 65586688 Dec 8 15:16 flannel-v0.13.1-rc1.tar
-rw-r--r-- 1 root root 4822 Dec 8 14:57 flannel.yml
[root@master01 ~]# docker load -i flannel-v0.13.1-rc1.tar
70351a035194: Loading layer [==================================================>] 45.68MB/45.68MB
cd38981c5610: Loading layer [==================================================>] 5.12kB/5.12kB
dce2fcdf3a87: Loading layer [==================================================>] 9.216kB/9.216kB
be155d1c86b7: Loading layer [==================================================>] 7.68kB/7.68kB
Loaded image: quay.io/coreos/flannel:v0.13.1-rc1
[root@master01 ~]#
复制flannel镜像打包文件到其他节点，并导入镜像
[root@master01 ~]# scp flannel-v0.13.1-rc1.tar node01:/root/
flannel-v0.13.1-rc1.tar 100% 63MB 62.5MB/s 00:01
[root@master01 ~]# scp flannel-v0.13.1-rc1.tar node02:/root/
flannel-v0.13.1-rc1.tar 100% 63MB 62.4MB/s 00:01
[root@master01 ~]# scp flannel-v0.13.1-rc1.tar node03:/root/
flannel-v0.13.1-rc1.tar 100% 63MB 62.5MB/s 00:01
[root@master01 ~]# ssh node01 'docker load -i /root/flannel-v0.13.1-rc1.tar'
Loaded image: quay.io/coreos/flannel:v0.13.1-rc1
[root@master01 ~]# ssh node02 'docker load -i /root/flannel-v0.13.1-rc1.tar'
Loaded image: quay.io/coreos/flannel:v0.13.1-rc1
[root@master01 ~]# ssh node03 'docker load -i /root/flannel-v0.13.1-rc1.tar'
Loaded image: quay.io/coreos/flannel:v0.13.1-rc1
[root@master01 ~]#
再次查看pod运行情况
[root@master01 ~]# kubectl get pods -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-7f89b7bc75-k9gdt 1/1 Running 0 39m
coredns-7f89b7bc75-kp855 1/1 Running 0 39m
etcd-master01.k8s.org 1/1 Running 0 40m
kube-apiserver-master01.k8s.org 1/1 Running 0 40m
kube-controller-manager-master01.k8s.org 1/1 Running 0 40m
kube-flannel-ds-zgq92 1/1 Running 0 19m
kube-proxy-pjv9s 1/1 Running 0 39m
kube-scheduler-master01.k8s.org 1/1 Running 0 40m
[root@master01 ~]#
提示：可以看到kube-flannel已经正常running起来了；
查看节点信息
[root@master01 ~]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
master01.k8s.org Ready control-plane,master 41m v1.20.0
[root@master01 ~]#
提示：可以看到master节点已经处于ready状态，表示master端已经部署好了；
将node01加入到k8s集群作为node节点
[root@node01 ~]# kubeadm join 192.168.0.41:6443 --token dz6bs3.ohitv535s1fmcuag \
> --discovery-token-ca-cert-hash sha256:330db1e5abff4d0e62150596f3e989cde40e61bdc73d6477170d786fcc1cfc67 \
> --ignore-preflight-errors=Swap
[preflight] Running pre-flight checks
[WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
[WARNING SystemVerification]: this Docker version is not on the list of validated versions: 20.10.0. Latest validated version: 19.03
[WARNING Service-Kubelet]: kubelet service is not enabled, please run 'systemctl enable kubelet.service'
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml'
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Starting the kubelet
[kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap... This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details. Run 'kubectl get nodes' on the control-plane to see this node join the cluster. [root@node01 ~]#
提示：执行相同的命令将其他节点加入到k8s集群，作为node节点；
在master节点上查看集群节点信息
[root@master01 ~]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
master01.k8s.org Ready control-plane,master 49m v1.20.0
node01.k8s.org Ready <none> 5m53s v1.20.0
node02.k8s.org Ready <none> 30s v1.20.0
node03.k8s.org Ready <none> 25s v1.20.0
[root@master01 ~]#
提示：可以看到master和3个node节点都处于ready状态；
测试：运行一个nginx 控制器，并指定使用nginx:1.14-alpine这个镜像，看看是否可以正常运行？
[root@master01 ~]# kubectl create deploy nginx-dep --image=nginx:1.14-alpine
deployment.apps/nginx-dep created
[root@master01 ~]# kubectl get pod
NAME READY STATUS RESTARTS AGE
nginx-dep-8967df55d-j8zp7 1/1 Running 0 18s
[root@master01 ~]# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nginx-dep-8967df55d-j8zp7 1/1 Running 0 30s 10.244.2.2 node02.k8s.org <none> <none>
[root@master01 ~]#
验证：访问podip看看对应nginx是否能够被访问到？
[root@master01 ~]# curl 10.244.2.2
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p> <p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p> <p><em>Thank you for using nginx.</em></p>
</body>
</html>
[root@master01 ~]#
提示：可以看到访问pod ip能够正常访问到对应nginx pod；到此一个单master节点，3个node节点的k8s集群就搭建好了；
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